Will, I agree with you absolutely 100%. That is what I try to do. I don't really "need" to do anything as I have enough planes to fly. So there's no pressure. But I am keen to keep experimenting with the polyurethane filling. I'm totally dedicated to foam cores in wings and have no interest in making hollow wings at all. But as yet, I haven't worked out my preferred method for the heavier wings, so the experimentation is all part of the process. Hopefully then when I get the new moulds, I'll have that sorted out (using the old moulds to develop the techniques meanwhile) and will be able to get onto making good Scratchos sooner. Shipping the Scratchos to Alex was a no-brainer as I know he's flown the Scratcho in the USA and I know he is excellent at fixing/ modifying stuff and doesn't mind things looking rough, as long as they fly well! But I can't promise anyone that I'll make one for them. It's what I want to do, but I don't want to put that pressure on myself, to have to make ones that are good enough to sell to people I don't know well. But I am hoping that things fall into place and that (without too much pressure) I can eventually make a new Scratcho every month or so which I can be proud of and happy to sell to another owner.

I have a question not about the plane, but about the music in the video. It mention a daughter's band.
Is there an album out? Or can I buy a CD or two from you?
I love that music style and have never known if there was a specific genre name for it to search.

Being unfamiliar with the whole gig, can I assume bandcamp.com gets a "sizeable" portion of the income? Do you know what the percentage is? Is there a way to contribute directly to the artists without a middle-man? Just feeling generous at the moment despite not being able to pay my own bills this month (well, child support was first and rent second, but everything else will get a late charge...but I still want to support "local and meaningful" artists).
I already purchased a download, but am still curious about a "donation".

I have fitted out a very light Scratcho using the first-attempt PU foam filled wing, the original experimental PU filled tails, and a very light fuse I made for the purpose.

Itís ready to fly, and the AUW is 869 grams. Thatís a big achievement for me. The lightest Scratcho Iíve built (the one Iím currently flying, with the ďvac bagged half-coresĒ) is just under 1200 grams.

The parts are all experiments, and I didnít go to any lengths to try and make this thing look perfect. But it does look pretty good anyway. I used cheap gear to fit it out, and tried to be as quick as possible (but it still blows me away how long it all takes! I can spend 20 minutes just working out which clevises to use Ö!)

The tails are nude carbon, as out of the moulds. They're very light, and I didn't paint them.

I used very cheap HobbyKing Hextronic servos throughout. HXT900ís for ailerons, and also in the nose for elevator and rudder. MG-14ís for flaps. Control snakes are nicrome fishing wire in Teflon outers.

I normally do an Aeromod-style bent piano wire horn for the rudder, which is very strong. But this time I just did a small carbon stalk, with ball link on top. Only two wing mounting bolts instead of my usual 4.

I didnít put any PU foam in the fuse boom. I thought for a while about that, because it does really add a lot of resilience to the boom. And since my mould tends to trap the fuz under the wing saddle, I nearly snapped the boom just getting it out of the mould! But I did want to go all-out for low weight with this one, so I decided against.

It needed barely any weight in the nose. I made up an AA Eneloop pack and it took just 15 grams of extra lead to balance. I could have put in a AAA pack and more lead at the tip, but I like the idea of a big battery pack, if weight allows.

I reckon this is about as light as itís practical to make a Scratcho, assuming it has to have a foam wing core, flaps and rudder.

Test flight sometime soon.

Images

Andrew.
Impressive as always.
maybe you next one should be a fast one.
write up a plan and follow it as they do on the raketenwurm vid. You are spending alot of time designing as you build. Whew you get it down to parrot style, follow instructions, you'll get them out in no time. What you are doing is still development.
I love seeing what you are doing with this and know it is going to get better.
Will.

Thanks Will. It's not that impressive really. They're fine for me or people I know but quality wise they're very basic. All I care about is that they look half decent, fly well, and most importantly that they're TOUGH!

I do have a fast one! I built it before the US trip and it's only been flown 4 times I think! It is very beautiful with fluoro colours, weighs 3.2kg with no ballast, has lead in the wings (Ampreg filled), wipers, servo covers etc. It's very nice but I'm scared of it! What I need is a really good 2.5kg one. It's amazing that Alex has taken his really crappy basic one to 267mph with no wipers, no servo covers ...

I have been developing plans. I have layup instructions and templates for fuse and wing, which I update regularly, and a folder full of notes and diagrams. But I'm still learning and experimenting with other materials and methods, so there's always change. I have 2 more Scratchos on the way - they were experimental foam core wings plus Ampreg, and they're very strong, and I'm now painting them out of the mould. Fuses done and just need to do one more set of tails. I've started engraving a number under the wing and recording its layup etc, because I'm totally losing track of how each one was made.

I haven't made much progress with getting moulds done from the excellent drawings you've done for me. Still putting out feelers, but no luck yet. I'm trying to get it done on the cheap, which doesn't help.

The project managers at my work often tell the design team, its time to finish design and development so we can get it into production.
But I know the feeling of wanting to finish it off as best you can.
I look forward to the day I can push the buy it now button on one of these!